What's the key difference compared to using the native Goals feature of Google Calendar and making the free/busy status from those events be visible to coworkers?
1) We purposely flip the free/busy time back and forth depending on your agenda and habit policy, without your intervention. With goals, it shifts, but it still appears as a busy block (unless you changed it by hand to free), which isn't quite accurate since it can move. Our approach is good for managers who want to be more available for their team.
2) Habits offers a lot more flexible in terms of defining schedule (days of week, min/max duration, defense strategy, etc). It also has some nice integrations with Slack that give you more control in fine-tuning your schedule each day.